Been fighting this problem with the pcm not having any rpm or spark the truck did run and start but then would have a problem if it stalled after warm up it would have no rpm or spark and would just crank
no rpm blip of spark.hpl
3 bar new update hopefully works.hpt
Check the crank sensor first. Make sure you have 12V and ground to it. If you have both, then check the continuity of the sensor output wire from sensor to the PCM.
didnt even think to do that ill check that next just replaced the crank sensor todayOriginally Posted by kevin87turbot
Typically no rpm/spark is a crank sensor issue
Checked wire I have no 12v reference coming from pcm guessing faulty pcm has any one found away to bypass the pcm to send signal to the ckp?
You could rig up a toggle switch between C1 pin 12 and a +12v source, then just flick the switch onoffonoffonoffonoff really fast at whatever you think the engine RPM should be. That should work fine. I don't know why more technicians who do this sort of thing every single day don't think of simple workarounds like this!
(probably because just looking at the service manual and, you know, finding and fixing the actual problem is easier and faster than all that silly bullshit)
Get a service manual. Look at the wiring diagrams. Follow the diagnostics for 'engine cranks but does not run'. It's not that hard. Guys doing this for a living would probably get, at most, paid 1 hour of labor to fix this.
I thought 12v usually comes from fuse panel, and just reference goes to PCM?
MAF is like that, but not CKP/CMP. 2006 Silverado for reference.
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